i have a 2.9 4x4 and a cossie and the v6 is by far the best for towing. you've got the torque from 500 - 3000 rpm from the v6 (as you probably know from your v6 although your 24v probably is a bit more powerful at top end), whereas with a cossie you've got nothing below 3000 when the turbo comes in cos it's low compression.
if your caravan (and you really should be shot for even contemplating this) is particularly heavy, you might have to really slip the clutch to pull away up hill or something.
i have no experience of towing with a cossie, but if you were to do it, maybe go for a T25 or something where you'll get some boost lower down.